1. If the rust stains have just appeared in the bucket and the area of the rust stains is not very large, you can use oxalic acid solution to wash it off, and then wipe it with clean water. The reason for this is that although the rust removal ability of oxalic acid solution is not very strong, it can protect the oxide film on the surface of the barrel and remove rust stains under the premise of minimizing the damage to the oxide film.
2. After crushed into powder with 3-4 vitamin C tablets, spread on the surface of the closed barrel, and then scrub with water several times to remove rust stains. This method is similar to washing with oxalic acid solution, you can choose to use according to your own convenience.
3. For rust stains and old stains, use 10% oxalic acid, citric acid and water mixture to soak the stained area, and then wipe it again with concentrated brine.
4. If there is fresh lemon, you can squeeze out the juice droplets and rub it on the rust stains by hand, repeat it several times until the rust stains of the closed bucket are removed, and then wash it with soapy water.
5. Can also be washed with dilute hydrochloric acid or dilute sulfuric acid (the editor reminds you to pay attention to the use of chemical reagents)